Kotlin学习笔记——ViewPager

#define 小毛驴 xml

使用方法

0. 在活动页面添加ViewPager，如果需要tab标签，在ViewPager里嵌套PagerTabStrip或PagerTitleStrip
1. 设计传送数据的类（一张图和一个标题就足够）
2. 编写ViewPager的适配器

   class ImagePagerAdapter(val context: Context, val itemList:MutableList<itemInfo>) : PagerAdapter() {
       val views = mutableListOf<ImageView>()
       init {
           for (item in itemList) {
               val view = ImageView(context)
               //view.layoutParams = ActionBar.LayoutParams(ActionBar.LayoutParams.MATCH_PARENT, ActionBar.LayoutParams.WRAP_CONTENT)
               view.layoutParams = ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)
   
               view.setImageResource(item.pic)
               view.scaleType = ImageView.ScaleType.FIT_CENTER
               views.add(view)
           }
       }
       override fun isViewFromObject(p0: View, p1: Any): Boolean = (p0 === p1)
   
       override fun getCount(): Int = views.size
   
       override fun destroyItem(container: ViewGroup, position: Int, `object`: Any) {
           container.removeView(views[position])
       }
   
       override fun instantiateItem(container: ViewGroup, position: Int): Any {
           container.addView(views[position])
           return views[position]
       }
   
       override fun getPageTitle(position: Int): CharSequence? {
           return itemList[position].desc
       }//与PagerTabStrip或配合使用
   
   }

3. 给PagerView添加适配器和页面改变的Listener

   class MainActivity : AppCompatActivity(), ViewPager.OnPageChangeListener {
       override fun onPageScrollStateChanged(p0: Int) {
       }
   
       override fun onPageScrolled(p0: Int, p1: Float, p2: Int) {
   
       }
   
   
       override fun onPageSelected(p0: Int) {
           Toast.makeText(this, p0.toString(), Toast.LENGTH_SHORT).show()
       }
   
       override fun onCreate(savedInstanceState: Bundle?) {
           super.onCreate(savedInstanceState)
           setContentView(R.layout.activity_main)
           //supportActionBar?.hide()
           var vp:ViewPager = findViewById(R.id.vp)
           val pics = arrayOf(R.mipmap.basic, R.mipmap.close, R.mipmap.debug, R.mipmap.edit)
           val list:MutableList<itemInfo> = mutableListOf()
           for (i in pics.indices) {
               list.add(itemInfo((i+1).toString(), pics[i]))
           }
           vp.adapter = ImagePagerAdapter(this, list)
           vp.currentItem = 0
           vp.addOnPageChangeListener(this)
   
           var title: PagerTabStrip = findViewById(R.id.title)
   
           title.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20f)
           title.setTextColor(Color.RED)
       }
   }